I. Field of the Invention
This invention relates to a method of mixing pulverulant materials by feeding a main pulverulent material and a compounding ingredient pulverulent material into a conveyor duct where air is fed under pressure of is drawn and a device for practicing the method. The pulverulent material herein referred to includes relatively large-grain pulverulent materials, granulated materials, pellets, tablets and the like.
II. Prior Art
Stated with reference to a plastic molding material by way of example, a conventional method of mixing pulverulent materials makes it practice to weigh a virgin material and a compounding material (as used a compounding material is, for example, a pulverized reclaimed materials) on a weigher in accordance with a preset mixing ratio and to mix the materials uniformly by a mixer.
The method described above, however, leaves the following problems to be improved.
Namely, first the method makes it necessary to install the weigher and the mixer in the midway of a material conveyor duct, with the result that the required device becomes large in size and expensive in price. Secondly, when the plastic moldings to be manufactured are changed in kind and mixing ratio, it is necessary to make change of materials by completely removing the material left in the mixer, thus requiring additional labor and reducing production efficiency.